The success of an endovascular aneurysm repair procedure depends upon precise preoperative measurement, said Florian Dick, Inselspital Bern, Switzerland, and the use of 3D computed tomography can now overcome the limited accuracy of conventional angiography in measuring complex anatomy.
In the “Imaging for endovascular repair of aortic aneurysm” session at the CX Symposium on Sunday 5 April 2009, Dick stressed the importance of the role of superior imaging modalities for identifying attachment zones (length, angulation, diameter, thrombus, calcification), measuring distances, and assessing tortuosity, to help in the selection of the right stent graft.
“The intrinsic limitations of 2D or planar images affect all possible measurements, including lengths, diameters, volumes, and angles,” said Dick. “3D or spatial imaging always emphasises the importance of the central luminal line, which can be introduced automatically as a reproducible reference line for all possible measurements you have.”
Dick added that his group’s ongoing research aims to prove the hypothesis that the performance of endovascular repair and its long-term results relate directly to preoperative anatomy coupled with optimal selection of the right device and precise deployment. The study collected 4,000 computed tomography images from 41 centres to be analysed with latest 3D imaging technology. “In one year’s time, we should have some interesting results,” Dick concluded.
Dick was supported in his assessment by Hence Verhagen, Erasmus University Medical Center, Rotterdam, The Netherlands. “All changed completely when endovascular repair was introduced,” he said. “We’ve learnt – probably the hard way – that accurate preoperative assessment is critical for the success of endovascular repair. Basically, 90% of the battle is won or lost before stepping into the operating theatre. Planning is extremely important and must be based in preoperative imaging,” Verhagen said.
“Imaging has become spectacular. You can scroll through the role body. Unfortunately, some of us are reluctant to use this, especially surgeons, because they think it’s either too difficult to learn, too difficult to use, too time-consuming, or too modern.”
Verhagen mentioned four user-friendly workstations: 3Surgery Vascular Imaging (3Mensio), Aquarius (TeraRecon), M2S Medical Metrx Solutions, and Vitrea (Vital Images). He explained how, with a couple of clicks, the professional can have a range of measurements. “It’s easy, it’s precise, saves a lot of time, radiation and contrast. It allows for a perfect planning. Most importantly, you shouldn’t guess, you should know,” concluded Verhagen.
Krassi Ivancev, Malmo University Hospital, Sweden, presented the latest studies of 3D angiography. “Literature supports the value of 3D computed tomograpy angiography superimpostion for cathterisation in transarterial chemoemobolization,” he said.
“This new imaging technique has yet to be fully applied to endovascular repair. It appears to offer clear advantages for catheterisation of target vessels, as well as evaluation of stent graft performance. 3D computed tomograpy angiography has the potential to allow intraoperative selection of branched and fenestrated stent grafts ‘off the shelf ‘,” he added.